An air bag assembly is designed to be incorporated into a vehicle to protect an occupant during a crash or collision. During a front end collision, a vehicle will be subjected to significant deceleration forces. If the deceleration forces are great enough, they will cause an unrestrained occupant to be pitched forward. An air bag assembly causes an air bag to be rapidly inflated in front of a vehicle occupant who is being pitched forward during a vehicle collision. The inflated bag prevents the occupant from striking a structural part of the vehicle interior (e.g., the vehicle instrument panel and/or windshield).
Typically, an air bag assembly includes: (i) a container; (ii) a folded air bag disposed in the container; and (iii) a fluid source disposed at least partially within the container. At the onset of a collision, the fluid source is actuated to discharge a flow of relatively high pressure fluid. The fluid flow rapidly (i) forces the air bag through a portion of the container and into the occupant compartment, and (ii) inflates the air bag to a predetermined configuration in front of an occupant who is being pitched forward by the force of the collision. The air bag retards forward movement of the occupant, to prevent the occupant from striking a structural part of the vehicle interior.
On the driver side of a vehicle, an air bag assembly is commonly incorporated into the steering wheel. On the passenger side of a vehicle, an air bag assembly is commonly incorporated into (or located in proximity to) the vehicle instrument panel. Moreover, on the passenger side of a particular make of vehicle, the specific manner which the air bag assembly is incorporated into the vehicle instrument panel has an effect on the design and function of an air bag for that make of vehicle. For example, in an air bag assembly located underneath the vehicle instrument panel, the air bag would have to be oriented to clear the legs of a seated occupant and would have to inflate upward in front of the vehicle instrument panel. On the other hand, in an air bag assembly incorporated into the portion of the vehicle instrument panel which is presented toward the vehicle occupant, the air bag would be positioned to deploy through the instrument panel toward the occupant. The bag would inflate to a generally cylindrical (or pillow) shape directly in front of a vehicle occupant. Still further, in an air bag assembly in which the air bag is deployed through the top of the instrument panel (referred to herein as a "top mounted" air bag assembly), the air bag is initially directed upward, toward the windshield of the vehicle. The air bag must then be quickly and effectively redirected so as to form a cushion between a vehicle occupant and the portion of the vehicle instrument panel presented toward the occupant.
A known way of deploying an air bag from a top mounted air bag assembly or from underneath a vehicle instrument panel is to:
(i) fabricate the air bag with multiple fluid chambers disposed in fluid communication with each other; PA1 (ii) inflate the chambers successively, such that as one chamber is substantially filled with fluid, the fluid is communicated from the one chamber to a successive chamber; and PA1 (iii) orient the chambers relative to each other such that at least one of the chambers, when inflated, is located in front of the instrument panel. PA1 (i) provide enough air bag material to form the multiple chambers; PA1 (ii) physically connect the chambers so that when the chambers are inflated at least one chamber will be oriented in front of the vehicle instrument panel; and PA1 (iii) provide fluid connections between the chambers which eliminate, minimize or account for turbulence as fluid is directed from one chamber to another.
U.S. Pat. Nos. 4,169,163 and 4,290,627 illustrate air bag assemblies using multiple chamber air bags. In each of the foregoing patents, a multiple chamber air bag has a chamber oriented in front of a vehicle instrument panel when the air bag is fully inflated.
Applicants believe that multiple chamber air bags, while useful, are somewhat complicated in their design and fabrication For example, applicants believe that in designing a multiple chamber air bag, one must:
Accordingly, applicants believe it is desirable to construct an air bag which has a single fluid chamber, which is simple and efficient to form, and which is specially designed to bend about a vehicle instrument panel to a position in front of a vehicle occupant. Applicants believe such an air bag can be designed with relative economy of material and without the kind of fluid turbulence which can occur when fluid is directed from one chamber to another. Applicants further believe that such an air bag can still have the ability to bend about a vehicle instrument panel to allow the air bag to be incorporated into a "top mounted" air bag assembly.
Applicants note that certain air bag constructions are allegedly designed for their relative economy of material (see e.g., U.S. Pat. No. 4,944,529). However, such constructions are believed to be capable, at most, of being deployed directly at a vehicle occupant and are not capable of bending in a predetermined manner about a vehicle instrument panel.